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Discussion Starter #1
I'm trying to finish an unfinished basement (I live in Virginia) and working on one problem at a time. Looking over my counties basement finishing guide and it states:


Insulation: A minimum of R-10(continuous roll type) or R-13 ( batt type installed between the studs) Insulation shall be provided with a vapor barrier, installed from the top of the basement wall to a depth of 10 feet below grade or to the top of the basement floor, whichever is less.


What is this stuff in my basement? Does it meet county code? Is it any good or garbage? I can only assume this stuff was used when the house was built in 2005. It looks like its rolled on and made up of two continuous sheets of plastic with fiber glass insulation in the middle.



Thanks!


 

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The insulation is behind the plastic. You need to make a small slit and see what is there. Most likely it is pink fiberglass.
 

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Discussion Starter #3 (Edited)
The insulation is behind the plastic. You need to make a small slit and see what is there. Most likely it is pink fiberglass.
I've cut into some of it already. It's yellow insulation sandwiched between two white plastic sheets, maybe 2-3 inches thick at most. One side of the white is what you see in the photos and the other white plastic side touches the foundation wall. I'm assuming the yellow insulation in the middle is typical fiberglass insulation. How do I know what the R value is of this stuff?

I hear mixed reviews about this stuff including mold issues. I also had a contractor look at the basement and he told me "This is the newest space age stuff and its great!" So I'm trying to find out if I need to rip this stuff down, leave it and put additional insulation, does this count as a vapor barrier?


You can see some of it sticking up through the plastic in this photo:



 

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What is this stuff in my basement? Does it meet county code?
You have to assume the house was built to code (at that time), inspected, and passed inspection. You can probably check with city on status of permits/inspections, but I don't think anybody would be allowed to live there until it passed inspection.

Some type of blanket insulation. You might be able to find a manufacturers mark on it. Possibly something similar to this:

https://www.certainteed.com/resources/30-45-052.pdf


Edit - new photo -- thats fiberglass
 

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In this link photo #3 looks like what you have and photo #4 is what they recommend.

A couple of problems with what you have are those payers of plastic prevent any inward drying which means any moisture coming through will be trapped behind the plastic. The contractor that referred to it as the "the newest space age stuff" needs to go back to energy school. The link above is from the people who help write the code guidelines.

As for vapor barriers the newest line of thinking is that allowing an assembly to dry is much better than trying to keep the moisture out. I see two window frames so suspect much of those areas is above grade, thus it can if needed dry to the outside. But below grade there is no outward drying. Latest thinking is to install a vapor barrier on the inside in the extreme north and on the outside in the extreme south. All others should not need (or want) a vapor barrier. Citation available, I just need to dig it out.

Bud
 
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Discussion Starter #7
Well I think your right. Interpreting the county code I posted it looks like what I got meets the code requirement. I am fortunate and have a really dry basement. I've never had moisture issues and I don't see any signs of it either. I understand that I can throw money at this project but I am not trying to create a net zero house or anything like that. What I was looking for really was an opinion if this was your house what would you do. The house is built into a pretty steep grade with front of the house having 4 feet exposed foundation wall and the back of the house has a full size sliding door that I can walk out and step right onto the grade out back. The temperature of the basement is always comfortable without any HVAC registers or returns in it / open.

Meeting code is what I probably already have. What are some reasonably cost effective insulation considerations would you implement if this was your project? I realize what I'm probably asking is hard to answer because of some infinite variables or even an energy audit. So if anyone has any questions I'm super happy to help answer. Thank you all for what you do!

Gabe
 

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Well I think your right. Interpreting the county code I posted it looks like what I got meets the code requirement. I am fortunate and have a really dry basement. I've never had moisture issues and I don't see any signs of it either. I understand that I can throw money at this project but I am not trying to create a net zero house or anything like that. What I was looking for really was an opinion if this was your house what would you do. The house is built into a pretty steep grade with front of the house having 4 feet exposed foundation wall and the back of the house has a full size sliding door that I can walk out and step right onto the grade out back. The temperature of the basement is always comfortable without any HVAC registers or returns in it / open.

Meeting code is what I probably already have. What are some reasonably cost effective insulation considerations would you implement if this was your project? I realize what I'm probably asking is hard to answer because of some infinite variables or even an energy audit. So if anyone has any questions I'm super happy to help answer. Thank you all for what you do!

Gabe
If you allow warm air to com into contact with the concrete 2 things can happen, condensation of water in the air and wicking moisture up from the ground thru the concrete. You have vapour barrier and insulation just at the min. to stop that. I would fill the wall cavities with insulation paying attention to a good fit. You want to limit the air movement in the cavities and limit the air from the basement from getting in the wall cavities.
 

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That might not be a vapor barrier on the insulation. I can see at least one rim joist cavity and I don't see any vapor barrier on the joist cavity. I would think that in your area, if they put a vapor barrier on the insulation, it would also be on the rim joist cavity.

Although Bud could very well be most correct on his opinion on vapor barrier in Virginia, you could research it on the internet for a week and still not get a clear answer if you should or should not have one. And it might be defined in your local building codes anyways.
 

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Discussion Starter #11
Looks like I found a post some of you already commented on with a similar product:

https://www.diychatroom.com/f103/basement-blanket-insulation-framing-558282/

SPS-1 - The joist cavity is a mixed bag. I have some spots with fiberglass batt and others with white Styrofoam. But I would need to look at it again since the Styrofoam areas may be only against the side of the attached garage wall.
 

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That is blanket insulation as SPS linked in post #4, probably the exact product (they may have part of the product packaging stapled up somewhere, just like you have to leave the window sticker on to pass inspection). It is installed by builders to meet the modern energy code without requiring framing basement walls, which makes it popular for spec houses . It has an R10 or R11. The poly film used is not a vapor barrier, they are usually perforated (there may be other products that are 1-sided with poly, those might be vapor barriers, but would probably be installed in a minimally-framed 24"o.c. wall just to hold it up).

The blanket should allow vapor to pass, but I'm sure too much moisture/leaks behind it and it could contribute to mold by not allowing water to dry quickly enough, especially if snug against the wall. That's probably the issues you've read about.

It can be left and framed in front, which you already have. You can add more batt insulation between studs, but if you're worried about cost, you won't gain much in terms of energy efficiency. However, along the walkout wall, you may want to add more insulation. I'm surprised the inspector didn't require more there to begin with.

In terms of adding a vapor barrier, I don't know the answer. Your code calls for it, but it may not be a good thing (except on the walk-out wall).

Off topic but you might need a security rail on the dining room slider.
 

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That looks just like what we build here but we change to wood framing above ground.
OP, I can't zoom in embedded pics and its a *png. Yours may be the first full concrete walkout complete with concrete headers on a non-brick house I've seen, can you attach a *jpg photo of that exterior shot I can use as an example in the future?
 

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Not much to see there but that header could be wood just above the window or just a double rim joist above, when it is concrete here, there would be 18x18 grid of 5/8 rebar with the extra over the hole.
 

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Discussion Starter #17 (Edited)
OP, I can't zoom in embedded pics and its a *png. Yours may be the first full concrete walkout complete with concrete headers on a non-brick house I've seen, can you attach a *jpg photo of that exterior shot I can use as an example in the future?

So the photos I used were low resolution screen captures from the original sale home inspection report. Looks like I don't have any of the back of the house but I will take some with a good camera later today and post them.


Just some additional information since there seams to be some interest. The house is a manufactured home. I'm assuming brought on a truck as 6 separate "Modules" then bolted together on site according to the data plate (attached). Didn't know this until the buyers home inspection but was told that the home was built "well" and "strong", "If it was built to handle 60mph on the back of a truck it was probably overbuilt". Other than some shoddy trade work here and there (ROOFER!!!) I'm happy with the rest of the home.



 

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Not much to see there but that header could be wood just above the window or just a double rim joist above, when it is concrete here, there would be 18x18 grid of 5/8 rebar with the extra over the hole.

Off topic but taking advantage of your nifty drawing, where I want to put a bedroom code requires a egress window (opposite corner from the current 2 windows in photo). I was thinking a Casement Window since I think it would create the smallest hole in the foundation wall. I also think I can avoid digging a well since enough area is available above grade for the required size window considering the 44 inches height requirment.. What does it take to put a hole / window in this foundation? My concerns are structural. Is it as easy as rent a saw make a hole or will I need to do some type of reinforcement first?



Code says:
Where windows are provided,
they shall have a sill height of not more than 44 inches from the floor; have a net clear
opening of 5.0 square feet at grade level & 5.7 square feet if above or below grade
level; see definition of grade level below: have a net clear opening height of 24 inches,
and have a net clear opening width of 20 inches. Note that A window with net clear
openings of 24”H x 20”W will not meet the minimum square foot opening
requirements.
 

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Off topic but taking advantage of your nifty drawing, where I want to put a bedroom code requires a egress window (opposite corner from the current 2 windows in photo). I was thinking a Casement Window since I think it would create the smallest hole in the foundation wall. I also think I can avoid digging a well since enough area is available above grade for the required size window considering the 44 inches height requirment.. What does it take to put a hole / window in this foundation? My concerns are structural. Is it as easy as rent a saw make a hole or will I need to do some type of reinforcement first?



Code says:
Where windows are provided,
they shall have a sill height of not more than 44 inches from the floor; have a net clear
opening of 5.0 square feet at grade level & 5.7 square feet if above or below grade
level; see definition of grade level below: have a net clear opening height of 24 inches,
and have a net clear opening width of 20 inches. Note that A window with net clear
openings of 24”H x 20”W will not meet the minimum square foot opening
requirements.
Keep in mind that windows are talked about with the rough in measurement. Egress is measured with the window installed fully open so your distance fro the floor may be 40 - 41" for the rough opening
Most times we do sliders and for rough we want 12 square ft.



The smallest was a casement window we did was all we could get was 2'0"x 3' 1 1/2" and I think that was small by a bit but was allowed because it was close.



So for yours do the joists run the same direction as the rim joists, are there any windows or other major bearing points above, like a beam in the living room or?


You would, do a well you would make a alcove with some sort of wall outside or just reshape the land out there.

I have never had to cut one out a coring company was always brought in for that job.
 

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The house is a manufactured home.
Aha! That explains it. Is the concrete a full 8" or 10" thick? If you look at your existing windows, they will either have a poured-in buck making the opening, or if a lack of that, then the opening has been rebar-ed at least similar to Neal's drawing or more. So if you cut in a new window, you won't have the rebar pre-installed to support a header and you will have to support it somehow because it only looks like 6" or 8" high from the pics. You could cut the concrete out all the way up, but then the requirements to tie both sides of the concrete together (to resist lateral loads) could be a little more complicated. The engineer you hire could work out those details.
 
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